Single walled carbon nanotube-metal oxide nanocomposites for reversible and reproducible storage of hydrogen

A review on MOFs synthesis and effect of their structural characteristics for hydrogen adsorption

Climate change is causing a rise in the need to transition from fossil fuels to renewable and clean energy such as hydrogen as a sustainable energy source. The issue with hydrogen's practical storage, however, prevents it from being widely used as an energy source. Current solutions, such as liquefied and compressed hydrogen storage, are insufficient to meet the U.S. Department of Energy's (US DOE) extensive on-board application requirements. Thus, a backup strategy involving material-based storage is required. Metal organic frameworks (MOFs) belong to the category of crystalline porous materials that have seen rapid interest in the field of energy storage due to their large surface area, high pore volume, and modifiable structure. Therefore, advanced technologies employed in the construction of MOFs, such as solvothermal, mechanochemical, microwave assisted, and sonochemical methods are reviewed. Finally, this review discussed the selected factors and structural characteristics of MOFs, which affect the hydrogen capacity.

Emerging Technology for a Green, Sustainable Energy-Promising Materials for Hydrogen Storage, from Nanotubes to Graphene-A Review

The energetic and climate crises should pose a challenge for scientists in finding solutions in the field of renewable, green energy sources. Throughout more than two decades, the search for new opportunities in the energy industry made it possible to observe the potential use of hydrogen as an energy source. One of the greatest challenges faced by scientists for the sake of its use as an energy source is designing safe, usable, reliable, and effective forms of hydrogen storage. Moreover, the manner in which hydrogen is to be stored is closely dependent on the potential use of this source of green energy. In stationary use, the aim is to achieve high volumetric density of the container. However, from the point of view of mobile applications, an extremely important aspect is the storage of hydrogen, using lightweight tanks of relatively high density. That is why, a focus of scientists has been put on the use of carbon-based materials and graphene as a perspective solution in the field of H₂ storage. This review focuses on the comparison of different methods for hydrogen storage, mainly based on the carbon-based materials and focuses on efficiently using graphene and its different forms to serve a purpose in the future H₂-based economy.

Cooperative physisorption and chemisorption of hydrogen on vanadium-decorated benzene

3d TM-decorated carbon composites have been proved to be a new generation of hydrogen storage materials. However, detailed hydrogen storage mechanisms are still unclear. Investigation of the H₂ dissociation and H migration on the 3d TM-decorated six-membered carbocycles is very critical for better understanding the hydrogen storage mechanism. In this paper, the processes of chemisorption and physisorption of multiple H₂ molecules on synthesized VC₆H₆ were simultaneously investigated for the first time. The Gibbs free energy calculations show that the optimal chemisorption pathway with the hydrogen storage capacity of 5.97 wt% is exothermic by 2.83 kcal mol⁻¹. Both the continuous hydrogenation giving the product of VC₆H₁₁–3H and reverse dehydrogenation could run smoothly at room temperature. The physisorption with a hydrogen storage capacity of 4.48 wt% will be exothermic by 13.49 kcal mol⁻¹. The H₂ molecules can be physisorbed at any temperature under 416 K and readily desorbed above 480 K at 1 atm. In summary, physisorption and chemisorption synergistically boost the hydrogen storage property of complex VC₆H₆. Our study provides a comprehensive picture of the interaction between hydrogen and VC₆H₆ and opens a new window for optimizing the future hydrogen storage materials.

We provide a comprehensive picture of hydrogen interaction with VC₆H₆ and a way of designing promising hydrogen storage materials.

Facile synthesis and characterization of a reduced graphene oxide/halloysite nanotubes/hexagonal boron nitride (RGO/HNT/h-BN) hybrid nanocomposite and its potential application in hydrogen storage

The hydrogen storage performance of hybrid nanocomposites composed of reduced graphene oxide, acid treated halloysite nanotubes and hexagonal boron nitride nanoparticles (RGO/A-HNT/h-BN) was studied.

Doping magnesium hydroxide with sodium nitrate: a new approach to tune the dehydration reactivity of heat-storage materials

Thermochemical energy storage (TES) provides a challenging approach for improving the efficiency of various energy systems. Magnesium hydroxide, Mg(OH)2, is known as a suitable material for TES at temperature T>300 °C. In this work, the thermal decomposition of Mg(OH)2 in the absence and presence of sodium nitrate (NaNO3) is investigated to adapt this material for TES at T<300 °C. The most notable observations described for the doped Mg(OH)2 are (1) a significant reduction of the decomposition temperature Td that allows tuning the dehydration reactivity by varying the NaNO3 content. The Td decrease by 25 °C is revealed at a salt content Y≤2.0 wt %. The maximum Td depression of some 50 °C is observed at Y=15-20 wt %; (2) the NaNO3-doped Mg(OH)2 decomposes considerably faster under conditions typical for closed TES cycles (at T>300 °C in vapor atmosphere) than a pure Mg(OH)2; (3) the morphology of the dehydration product (MgO) dramatically changes. Differential scanning calorimetry, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and vibrational spectroscopy (IR and Raman) are used to study the observed effects and to elucidate possible ways the NaNO3 influences the Mg(OH)2 dehydration and morphology of the dehydration product. The mechanism involving a chemical interaction between the salt and the hydroxide accompanied by nitrate embedding into brucite layers is discussed.